[Experimental mastitis in cows caused by Staphylococci, Streptococci and Corynebacteria]. / Eksperimentalni mastiti na kravi, predizvikani ot stafilokoki, streptokoki in korinebakterii.

Mastitis was experimentally induced in seven cows of the Black-and-white breed through the intramammary or i/v application of bacterial cultures of the encapsulated variant of Staph. epidermidis as well as of Str. agalactiae and Cor. pyogenes. The disease ran a course with high body temperature, strongly manifested inflammatory changes in the mammary gland, and altered phagocytic activity. It was found that the introduction into the mammary gland of a 'stable-specific' bovine blood serum in combination with the preparation nitrofuridine (a Shiff base of the 5-nitrofurfurol with sulfaguanidine) which boosts the phagocytic activity, had produced a therapeutic effect.

[Interdependence of milk production and the occurrence of subclinical mastitis in cows]. / Zavisimost mezhdu mlechnata produktivnost i chestotata na subklinichnite mastiti pri kravite

Studied was the milk productivity (milk yield and butterfat percent) of 255 normal and 255 diseased cows with subclinical mastitis, both groups pertaining to the Bulgarian Brown breed within the region of the Sofia Pedigree Breeding Inspection. All animals were examined at one and the same time during the period of their third lactation, and the milk productivity data obtained referred to the same period. It was established that there were no statistically significant variations between milk productivity data of the healthy cows and those of the cows with subclinical mastitis for a 300 day period. The relative number of cows with subclinical mastitis showing a milk yield of up to 4000 kg was lower as compared with the same number of the negatively reacting cows. On the other hand, cows showed yields of more than 4000 kg milk manifested reverse trends.

[Interbreed and interspecies variation in the occurrence of subclinical mastitis in cows and buffaloes]. / Mezhduporodni i mezhduvidovi razlichiia po otnoshenie na subklinichnite mastiti pri kravite i bivolitsite

Studied were for subclinical mastitis 3252 cows of the Bulgarian Brown breed, 1409 cows of the Bulgarian Simmenthal breed, 1082 cows of the Bulgarian Red cattle, 341 cows of the Iskar cattle, 1086 cows of the Black and White breed, and 418 buffalo-cows. Established were mathematically dependable variations with regard to the individual sensitivity to subclinical mastitis of the main cattle breeds reared in this country. Highest was the percent of subclinical mastitis in the cows of the Bulgarian Simmenthal breed - 28.22. Bulgarian Brown cows and the cows of the Bulgarian Red breed were equally affected with subclinical mastitis - 25.24 and 25.23 per cent, respectively. In the Iskar and Black and White cattle the values were 12.60 and 12.70 per cent, respectively, i.e., the per cent of subclinical mastitis was more than twice lower as compared with the first three breeds. Buffalo-cows showed high absolute and relative resistance both with regard to subclinical and to clinical mastitis.

[Morphologic characteristics of the udder in healthy cows and in those with subclinical mastitis]. / Morfologichna kharakteristika na vimeto pri zdrevi i sus subklinichen mastiti kravi

Studied were the values of 26 linear measurements of the udder in 50 normal cows and in 50 cows affected with subclinical mastitis, the animals used being of the Bulgarian Brown breed. A total of 19 indexes were established for each group.

[Interdependance between age, stage of lactation and occurrence of subclinical mastitis in cows]. / Zavisimost mezhdu v'zrastta, stadiia na laktatsiiata i chestotata na subklinichnite mastiti pri kravite

Examined were for subclinical mastitis within the period of the first to tenth lactation 3252 cows of the Bulgarian Brown breed, 1409 cows of the Bulgarian Simmental breed, 1082 cows of the Bulgarian Red breed, 314 cows of the Iskur breed, and 1086 cows of the Black Pied breed. It was established that with advancing in age the frequency of subclinical mastitis occurrence rose. This correlation varied in different breeds. In Iskur cattle the percentage of positively reacting cows in all lactations was more than twice lower than that in the Bulgarian Brown, Simmental, and Red cows. Highest frequency of occurrence as regards the various forms of subclinical mastitis was observed in the first and second month from the beginning of lactation; in later months it was found to drop to a varying extent with the different breeds, and in the ninth and tenth month it again rose. Highest percentage of subclinical mastitis during the first lactation month was established in Bulgarian Brown cows (44%), followed by Bulgarian Simmental cows (36.88%).